This is the flipper and tail of the same whale, seeming to lounge on the surface.
Humpback megaptera novaeangliae whales are in the family of baleen whales, the same family as Blue Whales and Sperm Whales, and are the family with the largest animals on earth. Humpbacks are mostly a dark gray/black color, but their flippers (pectoral fins) are mostly white, and look aqua-marine blue when seen from above the surface underwater. They can be up to 18 feet long, and are the longest appendages on any creature on earth. A cool factoid to know.
While I watched this pair of Humpbacks they sometimes seemed to be playing, and other times seemed to slap their fins on the water, maybe to stun prey fish.
Good birding, and steem on!